1. Field of the Invention
The present invention relates to a radiator, for vehicle use, used to exchange heat between the cooling water flowing in the radiator and the air flowing around the periphery of the radiator.
2. Description of the Related Art
In order to radiate heat generated from an engine mounted on a vehicle, an engine cooling system is arranged, and the main component of the engine cooling system is a radiator. In general, the radiator is composed of a flat core, in which a large number of tubes and fins are alternately arranged, and a pair of tank members provided on both sides of the core. In many cases, the core and the tank members are made of aluminum and are assembled by means of mechanical joining (screwing) or brazing.
In order to mount the related parts such as an electric fan on the radiator, it is necessary to form a mounting portion. For example, as shown in FIG. 5, in some cases, the mounting portion 75 for mounting an electric fan is formed in the upper frame 73a and the lower frame 73b of the bracket 72 surrounding the core (not shown). Concerning this structure, refer to the official gazette of JP-A-8-247689. A portion of the electric fan is attached to this mounting portion 75 by a fastening means such as a bolt and a nut.
As a comparative example, it can be considered that a nut to be used as the mounting portion is provided in each tank member. As shown in FIG. 6, the main body portion 82 of the nut 80 having the female screw hole 83 is inserted into the through-hole 87 of one wall portion 86, and the flange portion 84 is made to contact with the surface of the wall portion 86. Then, brazing is conducted using the brazing filler metal, which has been supplied between the wall portion 86 and the flange portion 84, so that the nut 80 is brazed to the tank member 85. In this case, a bolt (not shown) is screwed into the female screw hole 83 of the nut 80, and a portion of the electric fan is fixed to the tank member 35.
In the case where the nut 80 is attached onto the wall portion 86 of the tank member 85 by means of brazing in which the brazing filler metal is used, in order to prevent the deterioration of appearance caused when the brazing filler metal oozes out, in many cases, the brazing filler metal is supplied onto an inner circumferential face of the through-hole 87 of the wall portion 86 and spread outward in the radial direction. However, as the flange portion 84 is closely contacted with the wall portion 86, it is difficult for the brazing filler metal to spread out all over the contact face. Accordingly, there is a tendency for the joining strength of the nut 80 to the tank member 85 to be insufficient.